Bug #16912362 LOAD DATA INFILE CLAIMS TO BE HOLDING

'SYSTEM LOCK' IN PROCESSLIST

Analysis
=========
Show processlist shows 'System Lock' in 'State' field while
LOAD DATA INFILE is running.

thd->proc_info update is missing in LOAD DATA INFILE path.
Thus any request will get last unpdated status from lock_table()
during open_table().

Fix:
=======
Update state information from LOAD DATA INFILE path.

sql/sql_load.cc

 /*
-   Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -253,6 +253,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   {
     DBUG_RETURN(TRUE);
   }
+  thd_proc_info(thd, "executing");
   /*
     Let us emit an error if we are loading data to table which is used
     in subselect in SET clause like we do it for INSERT.